Chapter 16: The Cardiovascular System - The Blood

Question 1

what is blood

Answer 1

a liquid connective tissue
- 55% plasma
- 45% cellular elements

most cellular elements of blood last only hours, days or weeks and must be replaced continually

Question 2

what are the main functions of blood in the body
1. Transportation

Answer 2

1. transportation
   - blood transports oxygen from the lungs to the cells of the body and co2 from body cells to the lungs for exhaustion
   - carries nutrients from GI tracts to body cells & hormones from endocrine glands to target cells
   - transports nitrogenous waste such as urea, creatine, uric acid from body cells to kidney
   - = removed via urine

Question 3

what are the main functions of blood in the body
2. Regulation

Answer 3

Regulation
- helps maintain homeostasis of all body fluids
- regulate pH
- adjust body temp
- movement of fluid across blood capillary walls

Question 4

what are the main functions of blood in the body
3. Protection

Answer 4

Protection
- blood can clot which protects against its excessive loss from cardiovascular system after an injury
- defensive properties in immune system
- antibodies, interferons

Question 5

what are the two main properties of blood

Answer 5

1. 55% plasma (fluid portion)
2. 45% cellular elements (cells and cell fragments)

Question 6

what is a buffy coat

Answer 6

thin, pale layer you see in a blood sample after its been spun down in centrifuge. sits between plasma (top layer) and red blood cells (bottom layer)

• contains immune cells and clotting components of blood

Question 7

hematocrit

Answer 7

the percentage of total blood volume occupied by erythrocytes

normal range for
women: 38-46% (avg 42)
men: 40-54% (avg 47)

ex. hematocrit of 40 indicated that 40% of volume of blood is composed of erythrocytes

Question 8

what is plasma

Answer 8

when the cellular elements are removed from blood, a straw coloured liquid remains

92% water, 7% proteins and 1% solutes

Question 9

plasma proteins

Answer 9

those that are confined to blood
- maintaining proper plasma colloid osmotic pressure
- synthesized by hepatocytes (liver cells)

Question 10

albumins

Answer 10

account for 60% of plasma proteins, most abundant and main contributors to plasma colloid osmotic pressure

• serve as transport proteins

Question 11

globulins (three types)

Answer 11

account for 35% of the plasma proteins

1. alpha
   - transport iron, lipids and fat soluble vitamins
2. beta
   - transport iron, lipids and fat soluble vitamins
3. gamma
   - also known as immunoglobulins or antibodies
   - proteins that disable foreign substances (antigens) such as bacteria and viruses that invade the body

Question 12

fibrinogen
(and what is serum)

Answer 12

makes up 4% of plasma proteins and plays a key role in blood clotting

• when removed from plasma during the clotting process the remaining fluid is called serum

serum = plasma without its clotting proteins

Question 13

what are the cellular elements of the blood/principle components (3)

Answer 13

1. Erythrocytes (red blood cells)
   - transport oxygen from the lungs to body cells and deliver CO2 from body cells to the lungs
2. Leukocytes (white blood cells)
   - protect the body from invading pathogens and other foreign substances
3. Platelets
   - fragments of cells that do not have a nucleus
   - release chemicals that promote blood clotting when blood vessels are damaged

Question 14

hematopoiesis
(pr hemopoiesis)

Answer 14

process by which blood cells are formed

first occurs in the yolk sac of an embryo and later in the liver and spleen of a fetus

Question 15

bone marrow
- and 2 types

Answer 15

a soft tissue that fills the internal space of bones
- is the primary site of hematopoiesis in the last three months before birth and continues as the source of blood cells after birth, throughout life

1. red bone marrow
   - highly vascularized tissue that contains stem cells capable of developing into blood cells
   - capable of hematopoiesis
2. yellow bone marrow
   - consist of large adipose (fat) cells that store triglycerides

with increasing age:
bone ,arrow changes from red to yellow

Question 16

pluripotent hematopoietic stem cells (PHSCs)

Answer 16

about 0.05-0.1% of red bone marrow cells

• have the capacity to develop into all types of blood cells
• they first develop into myeloid stem cells and lymphoid stem cells

Question 17

precursor cell

Answer 17

arise from progenitor cells and eventually develop into the specific cellular elements of the blood

Question 18

Several terms are used to refer to the
formation of specific blood cells:

Answer 18

erythropoiesis: refers to the formulation of erythrocytes

luekopoiess: refers to the formation of leukocytes

thrombopoiesis: formation of platelets

Question 19

What are hematopoietic growth factors and why are they important?

Answer 19

They are substances that regulate the differentiation and proliferation of blood cells, ensuring proper development and maintenance of the blood.

Question 20

What is erythropoietin (EPO), where is it produced, and what triggers its release?

Answer 20

EPO is a hormone made by the kidneys in response to low oxygen levels in tissues; it stimulates red blood cell (erythrocyte) formation in red bone marrow.

Question 21

What is thrombopoietin (TPO), where is it produced, and what does it do?

Answer 21

TPO is a hormone made by the liver when platelet levels are low; it stimulates the formation of platelets from megakaryocytes in red bone marrow

Question 22

What are cytokines, and what role do they play in blood cell development?

Answer 22

Cytokines are local signaling molecules (paracrines/autocrines) secreted by various cells that regulate cell growth, differentiation, and immune responses in blood formation.

Question 23

What do colony-stimulating factors (CSFs) and interleukins do in hematopoiesis?

Answer 23

1. Convert pluripotent stem cells into committed progenitor cells
2. Stimulate development of leukocytes
3. Regulate mature leukocyte functions

Question 24

Erythrocytes (red blood cells RBCs)

Answer 24

contain the oxygen carrying protein hemoglobin (that gives whole blood its red colour)

• hemoglobin makes up 22% of cells weight and is made before the cell loses its nucleus

Question 25

What are the normal erythrocyte counts and how are they maintained?

Answer 25

males: 5.4 million/ uL females: 4.8 million/ uL to maintain these levels, the body produces 2 million new RBCs per second, matching the rate of RBC destruction

Question 26

Describe the structure and unique features of mature erythrocytes

Answer 26

- are biconcave, flexible discs (7–8 μm), lack a nucleus and organelles, and cannot reproduce or perform major metabolism - membrane proteins and glycolipids also act as antigens for blood groups (e.g., ABO, Rh)

Question 27

Erythrocytes are highly specialized for their:

Answer 27

oxygen transport function: - because they have no nucleus all of their internal space is available or oxygen transport - they lack mitochondria and generate ATP anaerobically they do not use up any of the oxygen they transport

Question 28

a hemoglobin molecule has two main parts:

Answer 28

1. globin: a protein composed of four polypeptide chains (2 alpha and 2 beta) 2. heme: a pigment (non protein) attached to each of the four chains - at the centre of each heme is an iron (Fe+) ion that can combine reversibly with one oxygen molecule - each iron ion can bind to one oxygen molecule = each hemoglobin molecule can bind to four oxygen molecules

Question 29

How does oxygen transport work in hemoglobin?

Answer 29

In the lungs, hemoglobin picks up oxygen and becomes oxyhemoglobin — this form is bright red. As blood flows to the tissues, hemoglobin lets go of the oxygen, which then diffuses into nearby cells. Hemoglobin that’s released its oxygen is called deoxyhemoglobin, which is dark red.

Question 30

Why is blood color different in arteries vs. veins?

Answer 30

- Arterial blood (from the lungs) is bright red because it’s full of oxygen-loaded hemoglobin. - Venous blood (returning from the body) is dark red because it has more oxygen-depleted hemoglobin

Question 31

🧪 How does hemoglobin carry carbon dioxide?

Answer 31

When blood flows through tissues, CO₂ enters the blood. Some of this CO₂ attaches to the globin part (the protein chains) of hemoglobin. This forms a compound called carbaminohemoglobin (fancy name, just means "hemoglobin + carbon dioxide").

Question 32

how does hemoglobin play a role in the regulation of blood flow & blood pressure:

Answer 32

nitric oxide (NO) is a gas hormone made by endothelial cells (the cells lining blood vessels) - nitric oxide can bind to hemoglobin - It does this by carrying and releasing nitric oxide - NO causes vasodilation, which boosts oxygen delivery where it’s needed most

Question 33

besides hemoglobin, erythrocytes also contain the enzyme carbonic anhydrase (CA)

Answer 33

catalyzes the conversion of carbon dioxide and water to carbonic acid, which in turn dissociates into a hydrogen ion and a bicarbonate ion - reversible reaction - it allows most of the carbon dioxide (about 70%) in blood to be transported in the form of bicarbonate ions (HCO3−).

Question 34

erythropoiesis and proerythoroblast

Answer 34

formation of erythrocytes - During this process, a pluripotent hematopoietic stem cell develops into a myeloid stem cell, which gives rise to a progenitor cell formation of proerythroblast - divides several times, producing cells that begin to synthesize hemoglobin

Question 35

How do red blood cells (RBCs) develop and mature?

Answer 35

Immature cells eject their nucleus, becoming reticulocytes, which enter the bloodstream from red bone marrow. Within 1–2 days, they mature into erythrocytes. The loss of the nucleus gives RBCs their biconcave shape

Question 36

hypoxia (oxygen deficiency at the tissue level)

Answer 36

low oxygen levels - may occur if too little oxygen enters the blood - may fall due to anemia or as a result of circulatory problems that reduce blood flow to tissues

Question 37

how does the body respond to low oxygen levels (hypoxia)

Answer 37

The kidneys release erythropoietin (EPO), which speeds up RBC production in bone marrow. This happens when oxygen delivery is low due to high altitude, anemia, or poor circulation - As more RBCs are produced, oxygen levels return to normal (negative feedback)

Question 38

negative feedback regulation of erythropoiesis

Answer 38

Question 39

What happens to red blood cells (RBCs) after 120 days?

Answer 39

Old RBCs wear out and are removed by macrophages in the spleen, liver, and bone marrow. Hemoglobin is split into globin (which becomes amino acids) and heme

Question 40

explain and understand the "The Erythrocyte Life Cycle"

Answer 40

use notes and chat

Question 41

leukocytes (white blood cells WBCs)

Answer 41

- have nuclei and other organelles but do not contain hemoglobin - colourless under a light microscope unless they are stained with specific dyes - far less numerous (about 500-10,000 cells per uL of blood)

Question 42

What are the five types of leukocytes and how are they grouped?

Answer 42

The five types are neutrophils, eosinophils, basophils, monocytes, and lymphocytes. Granulocytes (with visible granules): Neutrophils, Eosinophils, Basophils Agranulocytes (no visible granules): Monocytes, Lymphocytes

Question 43

How are granulocytes distinguished under a microscope?

Answer 43

Eosinophils: Red-orange granules, 2-lobed nucleus, stain with acidic dye (eosin) Basophils: Blue-purple granules, S-shaped nucleus (often hidden), stain with basic dye Neutrophils: Pale lilac granules, multi-lobed nucleus (2–5 lobes), stain neutrally Young neutrophils = band cells Mature = PMNs (polymorphonuclear leukocytes)

Question 44

How do monocytes and lymphocytes differ?

Answer 44

Monocytes: Largest WBC, horseshoe/kidney-shaped nucleus Lymphocytes: Small with a large round nucleus and thin rim of cytoplasm Lymphocytes make up 20–25% of WBCs (2nd most common) Neutrophils are the most common (about 60–70% of WBCs)

Question 45

what is immunity

Answer 45

the body ability to ward off damage or disease cause by these destructive agents known as: the immune system

Question 46

What is the role of leukocytes in the immune system?

Answer 46

Leukocytes (white blood cells) are essential for fighting infections, killing abnormal cells, and supporting immune responses - They travel via the bloodstream to sites of injury or infection, where they leave the blood to act directly

Question 47

macrophages

Answer 47

large immune cells that engulf and destroy: bacteria, virus, dead cells - start as monocytes (a type of white blood cell in the blood). - When monocytes leave the bloodstream and enter tissues, they enlarge and turn into macrophages what they do: 1. Phagocytosis: They "eat" harmful particles by surrounding and digesting them. 2. Clean-up crew: They remove dead cells and help clean up infections or damaged tissue. 3. Signalers: They alert other immune cells by releasing cytokines and presenting antigens to lymphocytes

Question 48

inflammation

Answer 48

a response characterized by redness, pain, heat, and swelling, serves as a signal that attracts phagocytes to the region of tissue damage; the phagocytes can then destroy any invading microbes in that area

Question 49

antibodies

Answer 49

proteins that disable foreign substances that are in body cells T cells and NK cells attack infected body cells and destroy cancer cells

Question 50

leukopoiesis

Answer 50

is the process of forming white blood cells (leukocytes) in the red bone marrow It starts with pluripotent hematopoietic stem cells. These stem cells split into two paths: 1. Myeloid stem cells → become granulocytes (neutrophils, eosinophils, basophils) and monocytes 2. Lymphoid stem cells → become lymphocytes (B cells, T cells, NK cells)